जॉइन Examsbookउत्तर : 2. "2/3"
In a purse there are 30 coins, twenty one-rupee and remaining 50-paise coins. Eleven coins are picked simultaneously at random and are placed in a box. If a coin is now picked from the box, find the probability of it being a rupee coin?5
प्र: In a purse there are 30 coins, twenty one-rupee and remaining 50-paise coins. Eleven coins are picked simultaneously at random and are placed in a box. If a coin is now picked from the box, find the probability of it being a rupee coin?
- 14/7false
- 22/3true
- 31/2false
- 45/6false
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उत्तर : 2. "2/3"
व्याख्या :
Answer: B) 2/3 Explanation: Total coins 30 In that, 1 rupee coins 20 50 paise coins 10Probability of total 1 rupee coins = 20C11 Probability that 11 coins are picked = 30C11 Required probability of a coin now picked from the box is 1 rupee = 20C11/30C11 = 2/3.